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stevenvh
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The analog line is the one which needs special attention. Depending on the signal level and frequency the following trick may be useful. Apply the analog signal to the central (shielded) wire. Also apply it to the input of an opamp used as a buffer (voltage follower). Put the output signal of the opamp to the shielding of your analog signal wire.

voltage follower

Since the signal on the shielding is the same as on the central wire there's no capacitance between the two (since they're the same potential), and the physical properties of the wire are not that important. But, while you keep the impedance of the signal's input, the impedance of the shielding is very low (it's the output of the opamp), and thus very well suited for dissipating external noise.
So you get high noise immunity together with non-critical wiring and your input may be high impedance.

The analog line is the one which needs special attention. Depending on the signal level and frequency the following trick may be useful. Apply the analog signal to the central (shielded) wire. Also apply it to the input of an opamp used as a buffer (voltage follower). Put the output signal of the opamp to the shielding of your analog signal wire. Since the signal on the shielding is the same as on the central wire there's no capacitance between the two, and the physical properties of the wire are not that important. But, while you keep the impedance of the signal's input, the impedance of the shielding is very low (it's the output of the opamp), and thus very well suited for dissipating external noise.
So you get high noise immunity together with non-critical wiring and your input may be high impedance.

The analog line is the one which needs special attention. Depending on the signal level and frequency the following trick may be useful. Apply the analog signal to the central (shielded) wire. Also apply it to the input of an opamp used as a buffer (voltage follower). Put the output signal of the opamp to the shielding of your analog signal wire.

voltage follower

Since the signal on the shielding is the same as on the central wire there's no capacitance between the two (since they're the same potential), and the physical properties of the wire are not that important. But, while you keep the impedance of the signal's input, the impedance of the shielding is very low (it's the output of the opamp), and thus very well suited for dissipating external noise.
So you get high noise immunity together with non-critical wiring and your input may be high impedance.

Source Link
stevenvh
  • 142.4k
  • 20
  • 443
  • 658

The analog line is the one which needs special attention. Depending on the signal level and frequency the following trick may be useful. Apply the analog signal to the central (shielded) wire. Also apply it to the input of an opamp used as a buffer (voltage follower). Put the output signal of the opamp to the shielding of your analog signal wire. Since the signal on the shielding is the same as on the central wire there's no capacitance between the two, and the physical properties of the wire are not that important. But, while you keep the impedance of the signal's input, the impedance of the shielding is very low (it's the output of the opamp), and thus very well suited for dissipating external noise.
So you get high noise immunity together with non-critical wiring and your input may be high impedance.